WASHINGTON — Millennium Space Systems of El Segundo, California, said Oct. 16 it has signed a contract with Space Systems Loral (SSL) to supply reaction wheel assemblies for an undisclosed commercial satellite constellation.

The press release said Millennium’s RWA1000 reaction wheel product is used to precisely point imaging satellites, which suggests the end customer is startup Skybox Imaging of Mountain View, California. Early this year Skybox, which is being purchased by technology giant Google, ordered 13 120-kilogram imaging satellites from Palo Alto, California-based SSL, a wholly owned subsidiary of Canada’s MDA Corp. that is known primarily for building large telecommunications satellites.

Millennium’s press release said each of the SSL-built satellites would carry four of the 1-kilogram RWA1000 assemblies and that the total order was for more than 50 units.

The reaction wheels will be built over the next 16 months in El Segundo, Millennium said, adding that it produces the hardware under an exclusive license from Sinclair Interplanetary of Canada.

Financial terms of the SSL contract were not disclosed.

“SSL’s production order is an early payback on our decision in 2012 to invest in and pursue internal development of spacecraft components,” Jeffrey Ward, Millennium’s vice president of product development, said in a prepared statement. “Vertical integration of this type gives us more control over quality, cost, and schedule — particularly at a time when the satellite component supplier base is contracting significantly.”

Millennium Space Systems also builds complete small satellites, primarily for U.S. government customers.

Jason Kim, Millennium’s director of strategic planning, referred questions about the SSL contract to Ward, who did not respond by press time.

Warren Ferster is the Editor-in-Chief of SpaceNews and is responsible for all the news and editorial coverage in the weekly newspaper, the spacenews.com Web site and variety of specialty publications such as show dailies. He manages a staff of seven reporters...